Studies Toward the Synthesis of Benzfuzed Azoles

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The thesis contains four chapters. The first two chapters describe the synthesis of 1-aryl-1H-benzotriazoles by copper-catalyzed C-N cross-coupling and palladium-catalyzed intramolecular C-H activation/C-N bond formation reactions. The third chapter deals with the synthesis of N-aryl benzimidazoles via palladium-catalyzed intramolecular C-H amination, while the fourth chapter focuses on PhI(OAc)2-promoted oxidative synthesis of benzfuzed azoles. I. Copper(I)-Catalyzed Synthesis of 1-Aryl-1H-benzotriazoles 1-Aryl-1H-benzotriazoles are among the most important classes of heterocyclic compounds in biological and medicinal sciences. This chapter describes copper(I)-catalyzed synthesis of 1-aryl-1H-benzotriazoles from 2-halophenylimino-2-phenyl-hydrazines by intramolecular C-N cross-coupling reaction (Scheme 1). A variety of substrates undergo reactions to give the target products in high yield. This procedure provides a straightforward route for the regioselecitve and efficient synthesis of functionalized 1-aryl-1H-benzotriazoles under external ligand-free conditions. Scheme 1. Copper(I)-Catalyzed Synthesis of 1-Aryl-1H-benzotriazoles II. Palladium(II)-Catalyzed Synthesis of 1-Aryl-1H-benzotriazoles C-H activation protocols are attractive because they make methodology atom economical, step efficient and obviate the need for preactivated substrate precursors. This chapter focuses on the synthesis of 1-aryl-1H-benzotriazoles from phenylimino-2-phenyl-hydrazines (Scheme 2). The substrates undergo intramolecular C-H activation followed by C-N bond formation reactions in presence of catalytic amount of Pd(OAc)2 to afford the corresponding 1-aryl-1H-benzotriazoles..
Supervisor: T. Punniyamourthy